Friday, July 29, 2011

Pseudo-Post

A couple reasons for this post.

First, I'd feel incomplete if I didn't have something for July. I haven't posted anything in a month, primarily because I've been focusing on my mathematics, and nobody wants to hear about that. Moreover, what philosophical ideas I have been thinking up with are so scattered and broad that I don't think I could write them down into a coherent post. I will note though that I'm starting to have serious concerns about the whole science of metaphysics--not that it's meaningless or something, but that it is not epistemologically first in the fashion of arm-chair metaphysicians. As bad as that sounds, I don't feel this needs to be accompanied by an embrace of scientism. Just look at this book. These are just idle thoughts at the moment though.

Second, and primarily, I want to advertise The Rational Gang to anyone who might stumble across my little corner of the internet. We will be starting a blog in the next week or two, so be on the lookout. I should also have a post on a Thomistic, non-Molinist, take on divine foreknowledge and human freedom in a week or so.

Also, if you don't know about Augustin-Louis Cauchy, read this Dictionary of Scientific Biography article on him. I quote it: "More concepts and theorems have been named for Cauchy than for any other mathematician (in elasticity alone there are sixteen concepts and theorems named for Cauchy)."

In his Cours d'Analyse, he proved the Fundamental Theorems of Calculus and Algebra, described partial fraction decomposition, devised convergence tests, and was the first to devise the ε-δ formulation of the limit (cf. this article by a prominent Cauchy historian; I love how it begins! A proper understanding of calculus is absolutely vital for understanding the power and limits of modern mathematical physics.). Of course Cauchy is also famous for complex integrals.

Since he was a devout Catholic, I've been wondering if he was well-versed in Thomism. He studied classics before becoming a mathematician, so it's possible. I'm not sure he wrote any treatise on the philosophy of mathematics, though.

Thanks Alan, those are some excellent resources! They will be very helpful. To be honest it is harder to find stuff on mathematics from on Aristotelian point of view, since, unlike Plato, Aristotle didn't lay as heavy an emphasis on mathematics. It probably has to do with the differences between Aristotle's more empirical approach and Plato's more idealist approach.

From what I have read, it seems that Aristotelian philosophy of mathematics does well making sense of the everyday mathematics your average person on the street uses, e.g. arithmetic, combinatorics, geometry, and other discrete disciplines. However, like you say, it would be interesting to see if an account of infinitesimals, calculus, the larger infinities, etc. could be given, while remaining a realist (rather than nominalist) theory of mathematics.

I was not aware of Cauchy's Catholicism. That is very interesting. Thanks again for all the links.

"From what I have read, it seems that Aristotelian philosophy of mathematics does well making sense of the everyday mathematics your average person on the street uses, e.g. arithmetic, combinatorics, geometry, and other discrete disciplines."

"However, like you say, it would be interesting to see if an account of infinitesimals, calculus, the larger infinities, etc. could be given, while remaining a realist (rather than nominalist) theory of mathematics."

St. Thomas, in his commentary on Aristotle's Physics, deals very well the "mathematical nominalist objection" to actual infinities in nature (be they infinitely large {cardinalities of Cantor sets}, infinitely small {infinitesimals}, etc.):

From In III Phys. lect. 7:[...] [Aristotle] says that it is impossible for the infinite to be separated from sensible things, in such a way that the infinite should be something existing of itself, as the Platonists laid down. For if the infinite is laid down as something separated, either it has a certain quantity (namely, continuous, which is size [magnitudo], or discrete, which is number [multitudo]), or not. If it is a substance without either the accident of size or that of number, then the infinite must be indivisible—since whatever is divisible is either number or size. But if something is indivisible, it will not be infinite except in the first way, namely, as something is called “infinite” [viz., "not finite"] [...], ["which is not surpass-able"], in the same way that a sound is said to be “invisible” [as not being by nature susceptible to being seen], but this is not what is intended in the present inquiry concerning the infinite, nor by those who laid down the infinite. For they did not intend to lay down the infinite as something indivisible, but as something that could not be passed through, i.e., as being susceptible to such, but with the passage having no completion.

So, it appears the mathematical nominalists are correct when it comes to mathematicals indirectly "separated [abstracted] from sensible things" (e.g., ∞, א, irrationals, etc., which are only ens rationis, "beings of reason" or "mind-dependent beings"), but they are incorrect in claiming that mathematicals of discrete (e.g., the number 2) and continuous quantity (e.g., a regular dodecahedron) can only be ens rationis (or our names of those ens rationis).

About Me

I'm Alfredo. I recently graduated with my Bachelor's degree from UCLA, and am currently a teaching assistant in the UCLA Department of Philosophy. I hope to apply for doctoral programs in philosophy soon. My main philosophical interests are currently in metaphysics, philosophy of mind, philosophy of religion, philosophy of language, and logic. I'm also an amateur pianist.